Geochemical & Rock Analysis


Elemental Analysis

The Earth & Planetary Sciences Department at UC Santa Cruz maintains a complete set of tools with which to measure elemental composition. X-ray fluorescence (XRF) is used to measure major, minor, and some trace elements in bulk solids, and electron probe micro analysis (EPMA) is used for spatially-resolved analyses of these elements. Trace and ultra-trace concentration measurements in both solids and liquids are performed inductively-coupled mass spectrometry (ICPMS), both quadrupole-based and high-resolution magnetic sector instruments. Additionally, through the Institute of Marine Sciences lab in our building, we have access to inductively-coupled optical emission spectroscopy (ICPOES), atomic absorption spectrophotometry, ion chromatography, gas chromatography, and gas chromatograph mass spectrometry.

  • Inductively-coupled Plasma Mass Spectrometry: In the spring of 2009 a new plasma analytical facility was established to replace our 15 year old Element 1 (the first of its kind in an academic lab in the U.S.). The new facility includes a Thermo Element XR (extended range) magnetic sector high-resolution ICPMS, an X-series quadrupole ICPMS, a Photon Machines Analyte 193H excimer laser system and Zygo NewView Element XR7200 Vertical Scanning Interferometer (for inspecting laser ablation pits). Combined with our complete suite of plasma introduction systems (desolvating nebulizers, flow injection system, Peltier-cooled spray chambers, etc.), we are equipped to measure most of the periodic table, over a wide range of concentrations, in solids and liquids of a wide range of compositions. A diverse user group includes marine chemists, igneous geochemists, archaeologists, inorganic chemists, geochronologists, environmental toxicologists, and paleo-oceanographers, to name a few.
  • X-ray Fluorescence Analysis: In the winter of 2006 we replaced our aging Philips AXS (one of the very first automated X-ray fluorescence spectrometers) with a very lightly-used, state-of-the-art XRF, donated by Quadra Mining. Used for only six months in 1998 at the Robinson Mine, Ely, NV, and mothballed for the next seven years, this Philips (now PANalytical) PW2404 comes equipped with a 4KW generator, a sharp-focus end-window RhXRF tube, an automated 96-sample changer, and a full complement of tube filters, analyzing crystals and detectors. This system utilizes all of the modern methods for spectrometric analysis and data reduction, and is capable of measuring a wide variety of materials, both solid and liquid, for major and trace element concentrations, qualitatively, semi-quantitatively, and quantitatively. Earth & Planetary Sciences at UCSC has been performing XRF analyses of the highest quality for 40 years, and with this new facility we are equipped to continue to do so for many years to come.
  • Electron Probe Microanalysis: Our ARL-SEMQ electron probe microanalyzer, was acquired in 1992 and upgraded to run on the Advanced Microbeam interface and Probe for Windows software. The system has 9 wavelength-dispersive spectrometers, six fixedElectron Probe and three scanning, which allows for very rapid major and minor element analysis of common silicate minerals (as fast as ten seconds per spot). The unit is also fitted with EDS, as well as secondary, backscattered and cathode-luminescence imaging. The software allows for X-ray mapping based on the output of the wavelength-dispersive detectors, and allows for fully automated analysis using mapped digital shapes, transects, and points. Quality of the elemental analysis data is very high due to rapid analysis time and excellent filament stability.

W.M. Keck Isotope Laboratory

WM Keck LabProjects covering earth sciences, marine sciences, environmental science and archaeology frequently use the W.M. Keck Isotope Laboratory facilities for high precision isotope measurements. Non-UCSC scientists are invited to use the facilities. The W.M. Keck Isotope Laboratory comprises two mass spectrometers and wet chemical labs all housed in a class 1000 suite of clean labs. For more information on the facilities available and use of the facilities contact Dr. Don Bard.


Microscopy and Imaging

Earth scientists have access to the campus Microscopy Center. This lab has both scanning and transmission electron microscopes, light microscopes equipped for photography and digital image capture, image analysis computers, photographic equipment for copying, and a complete black and white darkroom for printing. The scanning electron microscope is equipped with secondary (SE) and backscattered electron (BSE) detectors and an energy dispersive X-ray spectrometer (EDS) for the analysis of minerals. The SEM is also capable of direct, digital acquisition of images and X-ray spectra.One of the facility's transmission electron microscopes is equipped with a double tilt goniometer stage and an energy dispersive X-ray spectrometer useful for mineral analysis and diffraction. In addition, the lab has specimen preparation equipment for many types of samples including a vacuum evaporator, sputter coater, and ion thinner. Contact Dr. Ben Abrams for more information.

The Thermo-Chronology/Tectonics group also maintains a suite of microscopic equipment including petrographic microscopes; grain picking and viewing microscopes; a Vertical Scanning Interferometer; and digital image capture.

Additionally, the department's Electron Microprobe Lab (see above) has BSE, SE, EDS, and cathode luminescence imaging with digital image capture. Also house in this lab is a cathode luminescence microscope for viewing larger luminescence features than can be viewed in the electron microprobe.  


Rock Preparation

The Earth & Planetary Sciences’ Rock Preparation Facility is fully equipped to aid researchers in petrographic section making, rock crushing, sample sieving, and mineral separation, with a full-time technical staff member to oversee the functioning of this facility. The facility includes equipment for:

  • thin sectioning (slab saws, rolling-table trim saws, thin-section cut-off saw and grinder, kerosene-cooled trim saw for delicate material, customized rock-coring drill press, vacuum-impregnation apparatus, steel grinding laps, gem faceter, automated colloidal silica section polisher, hand-polishing laps with a wide variety of media, power feed rock saw),
  • rock crushing/sieving (jaw crushers, swing-mill, disk-mill, automated agate mortar and pestle, sieve-shaker, brass sieves, sandblaster), and
  • mineral separation (heavy liquids separation labware and chemicals, magnetic separator, shaker table, mica table).

Stable Isotope Laboratory

The Stable Isotope Laboratory is a state-of-the-art facility that houses five isotope ratio mass spectrometers for the isotopic analyses of carbon, nitrogen, hydrogen and oxygen species in solid and liquid samples. Stable Isotope LabSamples can either be analyzed from natural abundance or, on some instances, enriched sources. Front-ends for the IRMS's include: two automated carbonate devices, and a full suite of continuous flow peripheral devices. This facility is open to the UCSC community and is a vital research resource for many faculty, researchers and students in the Earth & Planetary Sciences Department. The laboratory is supported by the National Science Foundation, the UCSC Office of Research, the Division of Physical and Biological Sciences, the Earth and Planetary Sciences Department, and the Ocean Sciences Department.


Geochronology

Geochrnology Facilities

The Geochronology and Tectonic Processes group maintains a complete set of instrumentation and procedures for measuring U-Th/He thermochronometry and U-Pb age dating. This includes the Hourigan-designed, built, and coded, fully automated helium extraction line, and a Photon Machines Analyte 193 excimer laser system, which can be connected to both the He extraction line and the ElementXR for spatially-resolved grain analyses. A Zygo New View 7200 Vertical Scanning Interferometer is used for depth profiling and analysis of pit morphology.

The Surface Processes group in the department of Earth and Planetary Sciences maintains a cosmogenic isotope preparation lab for extraction of 10Be and 26Al for acceleration mass spectrometry measurement. Facilities include sample digestion equipment (open beaker, microwave and bombs), heated sonicating baths for leaching, and all necessary lab ware and clean room laboratory space.


X-ray Diffraction

The department maintains a PANalytical PW3040/60 X'Pert PRO MPD X-Ray diffractometer for characterization of powdered crystalline materials. The instrument uses a 3kW ceramic PW3373/10 LFF X-Ray tube with a Cu anode. The X'celerator detector, implements the latest RTMS (Real Time Multiple Strip) X-ray detection technology and allows data collection at rates about 100 times faster than conventional single-point counters.The instrument is outfitted with adjustable slits for incident and diffracted beams that balance the needs of resolution, peak intensity and background minimization.  The instrument is suited for qualative and quantitative analysis of structures, phases, preferred crystal orientations (texture), and other structural parameters, such as average grain size, crystallinity, strain, and crystal defects.

Further questions regarding XRD lab use or capabilities of the XRD instrument, contact The Department of Earth and Planetary Sciences Technical Staff at: epstech@acg.ucsc.edu